The hypothesis of the 1st and 3rd authors (see record 1983-27705-001) that a conceptual limitation underlies 3-yr-olds' difficulty with false-belief attribution was tested against 3 competing hypotheses. Results from 2 experiments involving 101 3- and 4-yr-olds show that false-belief attribution remained difficult for younger 3-yr-olds, despite their retention of essential facts and attempts to make expectations more explicit and prevent pragmatic misinterpretation. Findings strengthen the original hypothesis, specified as the inability to assign conflicting truth values to propositions. This hypothesis can explain why 3-yr-olds find pretend play, the distinction between expected and achieved outcomes, the real–imaginary distinction, and level 1 perspective taking easier to understand than false belief, the reality–appearance distinction, and level 2 perspective taking. (PsycINFO Database Record (c) 2016 APA, all rights reserved)